1. Field of the Invention
The present invention relates to an improved way of and means for producing electrical power from a network of metal-air Fuel Cell Battery (FCB) subsystems so that the peak power requirements of an electrical load (e.g. motor, appliance, machinery, tools, etc.) can be satisfied independent of the total amount of metal-fuel remaining within the system at any instant of time.
2. Description of the Prior Art
There is an increasing demand for electrically-powered vehicles in our society. As such, numerous methods have been proposed for supplying electric power to such electric vehicles.
One method of providing electrical power to such vehicles involves using hydrogen-based fuel cells. While this technique appears promising in space applications, the use of hydrogen as a fuel source in automobiles presents numerous problems including, for example, the volatility of hydrogen, special fuel-handling procedures, fuel inefficiency, and the like.
Alternative approaches to generating electrical power include the use of conventional battery technology configured together in various arrangements. With such technology, however, it is not possible to construct a vehicle that has the capacity to travel long distances without recharging its electric batteries. Factors which contribute to such limitations include the weight of the batteries, and the low volumetric power densities associated with conventional battery technology.
The use of solar-energy has also been proposed to supply electrical power to electric vehicles. Presently, this approach is not feasible due to the inefficiencies of photo-voltaic cells and energy storage capacities of commercial storage batteries.
Metal-air fuel cell battery (FCB) technology offers great promise in its capacity to produce relatively large amounts of electrical power in a continuous manner by reacting air and metal, such as zinc, in the presence of an electrolyte and a catalyst. U.S. Pat. No. 5,250,370 to Applicant discloses a tape-based metal-air FCB system for producing electrical power using such principles in systems having markedly improved electrical power density characteristics. Despite such promise offered by metal-air FCB technology, such technology is not without its problems.
For example, the degree to which metal-fuel tape is discharged by a metal-air FCB system depends on the electrical loading conditions imposed thereon during power generation operations. Thus, when electrical loading is heavy, the metal-fuel tape is completely consumed and electrical power efficiently generated. However, when electrical loading is light, the metal-fuel tape is only partially consumed and electrical power inefficiently generated.
In practical applications, the electrical loading conditions imposed on the output circuitry of a metal-air FCB system will vary over time and in response to conditions associated with the external environment. Addressing this problem, it is possible to couple together the output power of several metal-air FCB systems of the type disclosed in U.S. Pat. No. 5,250,370 so that the combined output power of the resulting system is significantly greater than the individual output powers and thus capable of meeting the peak power requirements of the electrical load connected to the resulting system.
In such cases when the demand for electrical power by the load varies over time and/or in response to changing environmental conditions, then it might be necessary or otherwise desirable to operate (i.e. switch-in) one or more of the metal-air FCB (sub)systems in the resulting system so that the combined output power is sufficient to satisfy the peak power requirements of the load. Notably, the use of this power control method over time will result in a rapid depletion of the metal-fuel in certain of the metal-air FCB subsystems that have been frequently operated, but not in other metal-air FCB subsystems that have been operated less frequently. Then when the power demanded by the load increases to its peak power demand value, the resulting FCB system will lack the capacity to generate a sufficient amount of output power to meet the peak power requirements of the electrical load.
Thus there is a great need in the art for an improved way of and means for generating electrical power from metal-air FCB systems so that the peak power requirements of electrical loads connected thereto can be met in a satisfactory manner while overcoming the shortcomings and limitations of prior art technologies.